Retrolisthesis and lumbar disc herniation: a preoperative assessment of patient function.

BACKGROUND CONTEXT: Retrolisthesis is relatively rare but when present has been associated with increased back pain and impaired back function. Neither the prevalence of this condition in individuals with lumbar disc herniations nor its possible relation to preoperative back pain and dysfunction has been well studied. PURPOSE: The purposes of this study were as follows: (1) to determine the prevalence of retrolisthesis (alone or in combination with other degenerative conditions) in individuals with confirmed L5-S1 disc herniation who later underwent lumbar discectomy; (2) to determine if there is any association between retrolisthesis and degenerative changes within the same vertebral motion segment; and (3) to determine the relation between retrolisthesis (alone or in combination with other degenerative conditions) and preoperative low back pain, physical function, and quality of life. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: A total of 125 individuals were identified for incorporation into this study. All patients had confirmed L5-S1 disc herniation on magnetic resonance imaging (MRI) and later underwent L5-S1 discectomy. All patients were enrolled in the Spine Patient Outcomes Research Trial (SPORT) study; data were obtained from the multi-institutional database comprised of SPORT patients from across the United States. OUTCOME MEASURES: Retrolisthesis, degenerative change on MRI, and Modic changes. METHODS: MRI scans of the lumbar spine were assessed at spinal level L5-S1 for all 125 patients. Retrolisthesis was defined as posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral endplate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. RESULTS: The overall incidence of retrolisthesis at L5-S1 in our study was 23.2%. Retrolisthesis combined with posterior degenerative changes, degenerative disc disease, or vertebral endplate changes had incidences of 4.8%, 16%, and 4.8% respectively. The prevalence of retrolisthesis did not vary by sex, age, race, smoking status, or education level when compared with individuals with normal sagittal alignment. However, individuals with retrolisthesis were more likely to be receiving workers' compensation than those without retrolisthesis. Increased age was found to be associated with individuals having vertebral endplate degenerative changes (both alone and in conjunction with retrolisthesis) and degenerative disc disease. Individuals who had retrolisthesis with concomitant vertebral endplate degenerative changes were more often smokers and had no insurance. The presence of retrolisthesis was not associated with an increased incidence of having degenerative disc disease, posterior degenerative changes, or vertebral endplate changes. No statistical significance was found between the presence of retrolisthesis on the degree of patient preoperative low back pain and physical function. Patients with degenerative disc disease were found to have increased leg pain compared with those patients without degenerative disc changes. CONCLUSIONS: We found no significant relationship between retrolisthesis in patients with L5-S1 disc herniation and worse baseline pain or function. It is possible that the contribution of pain or dysfunction related to retrolisthesis was far overshadowed by the presence of symptoms caused by the concomitant disc herniation. It remains to be seen whether retrolisthesis will affect outcome after discectomy in these patients.     

Quantifying the magnitude of risk for balance impairment on falls in community-dwelling older adults: a systematic review and meta-analysis

ObjectivesTo evaluate and summarize the evidence linking balance impairment as a risk factor for falls in community-dwelling older adults.Study Design and SettingSystematic review and meta-analysis. English language articles in MEDLINE, EMBASE, CINAHL (1988–2009), under keywords of accidental falls, aged, risk factors, and hip, radius, ulna, and humerus fractures; and bibliographies of retrieved articles. Community-dwelling older adults in a prospective study, at least 1-year duration, age more than 60 years, and samples not specific to a single disease-defined population were included. Sample size, inclusion/exclusion criteria, demographics, clinical balance measurement scale, type of fall outcome, method of fall ascertainment, length of follow-up, and odds ratio (OR) or risk ratio (RR) were extracted. Studies must have reported adjustment for confounders. Random effects meta-analysis to generate summary risk estimate was used. A priori evaluation of sources of heterogeneity was performed.ResultsTwenty-three studies met the selection criteria. A single summary measure could not be calculated because of the nonequivalence of the OR and RR, producing an overall fall risk of RR of 1.42 (1.08, 1.85) and OR of 1.98 (1.60, 2.46).ConclusionsBalance impairment imparts a moderate increase on fall risk in community-dwelling older adults. The type of fall outcome, the length of follow-up, and the balance measurement tool impact the magnitude of the association. Specific balance measurement scales were identified with associations for an increased fall risk, but further research is required to refine recommendations for their use in clinical practice.     

PET network abnormalities and cognitive decline in patients with mild cognitive impairment.

Temporoparietal and posterior cingulate metabolism deficits characterize patients with Alzheimer's disease (AD). A H(2)(15)O resting PET scan covariance pattern, derived by using multivariate techniques, was previously shown to discriminate 17 mild AD patients from 16 healthy controls. This AD covariance pattern revealed hypoperfusion in bilateral inferior parietal lobule and cingulate; and left middle frontal, inferior frontal, precentral, and supramarginal gyri. The AD pattern also revealed hyperperfusion in bilateral insula, lingual gyri, and cuneus; left fusiform and superior occipital gyri; and right parahippocampal gyrus and pulvinar. In an independent sample of 23 outpatients with mild cognitive impairment (MCI) followed at 6-month intervals, the AD pattern score was evaluated as a predictor of cognitive decline. In this MCI sample, an H2(15)O resting PET scan was carried out at baseline. Mean duration of follow-up was 48.8 (SD 15.5) months, during which time six of 23 MCI patients converted to AD. In generalized estimating equations (GEE) analyses, controlling for age, sex, education, and baseline neuropsychological scores, increased AD pattern score was associated with greater decline in each neuropsychological test score over time (Mini Mental State Exam, Selective Reminding Test delayed recall, Animal Naming, WAIS-R digit symbol; Ps<0.01-0.001). In summary, a resting PET covariance pattern previously reported to discriminate AD patients from control subjects was applied prospectively to an independent sample of MCI patients and found to predict cognitive decline. Independent replication in larger samples is needed before clinical application can be considered.     

Small proportions: what to report for confidence intervals?

The original article to which this Erratum refers was published in Pharmacoepidemiology and Drug Safety 2005; 14: 239–247.     

Risk Factors for a First Febrile Seizure: A Matched Case-Control Study

Summary We conducted a matched casecontrol study to identify risk factors for first febrile seizures, with special emphasis on characteristics of the acute illness episode. Cases were identified through hospital emergency departments; controls were identified through outpatient clinics and emergency departments. Sixtynine children with first febrile seizures and no history of previous unprovoked seizures were matched for age (±6 months), site of routine pediatric care, and date of visit (±weeks) with 1 or 2 febrile controls who had no history of previous febrile or unprovoked seizures. Medical records for the index visit were reviewed, and parents were interviewed by telephone. Illness characteristics examined included height of temperature, type of underlying illness, contact with a physician during the illness but before the index visit, and use of acetaminophen or decongestants. Family history of febrile and of unprovoked seizures, sociodemographic characteristics, daycare use, and selected preand perinatal variables were also studied. On multivariable analysis, significant independent risk factors were height of temperature, history of febrile seizures in a firstor in a higher degree relative. Gastroenteritis as the underlying illness had a significant inverse (i.e., protective) association with febrile seizures. Maternal smoking during pregnancy was a marginally significant predictor of febrile seizures.     

Regulation of CD59 expression on K562 cells: effects of phorbol myristate acetate, cross-linking antibody and non-lethal complement attack.

CD59 is the major membrane attack complex of complement (MAC) inhibiting protein on human cells. Its regulation is therefore an important factor in determining the fate of cells at sites of complement activation. We have chosen the K562 erythroleukaemia cell line as a model for studies of the regulation of CD59 expression, because it has previously been reported that phorbol 12-myristate 13-acetate (PMA) caused a 15-fold up-regulation of CD59 mRNA in these cells, implying a substantial capacity for CD59 synthesis. However, no assessment of CD59 protein expression was made in these studies. We show here that surface expression of CD59, as assessed by flow cytometry, was increased four-fold over a 16-hr incubation with PMA, whereas surface expression of decay-accelerating factor (DAF) (CD55) and membrane cofactor protein (MCP) (CD46) was not altered. The newly expressed CD59 was functionally active and anchored through glycosyl-phosphatidylinositol (GPI). Increased expression was dependent upon de novo protein synthesis. CD59 released into cell supernatant was also increased seven-fold by PMA, this 'secreted' CD59 retained its GPI anchor. Non-lethal complement attack did not alter CD59 expression but antibody cross-linking of CD59 caused a rapid loss of the CD59-antibody complexes. However, CD59 was quickly restored to pre-attack levels. This rapid restoration was not dependent upon protein synthesis, suggesting release from preformed stores.     

Nutrition and aging: nutritional status of "apparently healthy" elderly (Dutch nutrition surveillance system)

In a nationwide survey the nutritional status was assessed of 539 apparently healthy, independently living elderly aged 65-79 years. Anthropometric data showed no energy deficits. The prevalence of anemia was 4 and 1% among men and women, respectively. Many elderly showed a low level of 25-hydroxyvitamin D in plasma (less than 31 nmol/L: men 35%; women 43%), indicating a marginal status. Although the prevalence of low blood levels of folate, pyridoxal-5'-phosphate, and total carotenoids was higher among the elderly than among younger adults, clear (clinical) signs of nutritional deficiencies were not observed. Prevalence of obesity (13%), hypercholesterolemia (38%), and hypertension (63%) was found to be high, the percentages being higher for women than for men. Several indicators of the nutritional status appeared to differ among age groups. It is concluded that few differences can be considered as being due to physiological aging, which finding should be reflected in reference values for elderly people.     

Factors related to renal haemodynamics in young type-1 diabetes mellitus patients

The influence of metabolic control (HbA_1c), noradrenaline (NA) and insulin-like growth factors (IGF-I and IGF-II) on renal function and size was investigated in 11 insulin-dependent diabetes mellitus patients aged 11–17 years. Renal function was evaluated in terms of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Renal size was determined as renal parenchymal volume (RPV) by ultrasonography. The patients' HbA_1c values ranged from 8.2% to 12.9% (normal range 5.5–8.5%) and their GFR and ERPF were higher than normal. Their IGF-II values were higher, and NA and IGF-I levels were lower than those of healthy controls. Inverse correlations between NA and GFR (r=–0.66) and NA and ERPF (r=–0.63) were found. No correlation was found between serum IGF-I and renal functional parameters. The IGF-II values correlated with GFR and HbA_1c (r=0.63,r=0.70 respectively). There were linear correlations between RPV and GFR, RPV and ERPF, HbA_1c and GFR, and ERPF and RPV. Decreased NA concentrations and increased IGF-II values appear to be factors contributing to renal hyperfunction in these patients.     

Chondrocyte-seeded hydroxyapatite for repair of large articular cartilage defects. A pilot study in the goat

The aim of this study was to evaluate the potential for restoration of a large cartilage defect in the goat knee with hydroxyapatite (HA) loaded with chondrocytes. Isolated chondrocytes were suspended in fibrin glue, seeded on top of the HA, and then the composite graft was implanted in the defect. After transplantation, cell behaviour, newly synthesised matrix and the HA–glue interface were assessed histologically after 2, 4, 12, 26 and 52 weeks. Special attention was paid to the incorporation process of HA in the subchondral bone and interactions between this biomaterial and the fibrin-glue–chondrocyte suspension.

Chondrocytes in the glue proved to survive the transplantation procedure and produced new metachromatically stained matrix two weeks after implantation. The glue–cell suspension had penetrated the superficial porous structure of the HA. Four weeks after surgery, islands of hyaline-like cartilage were observed at the HA–glue interface. A layer of fibrous tissue was formed surrounding the HA graft, resulting in a relatively instable fixation of the HA in the defect. This instability of the graft in the defect, possibly together with early weight bearing, resulted in a gradual loss of the newly formed hyaline cartilage-like repair tissue. Progressive resorption of the HA occurred without any sign of active bone remodelling from the host site. One year after surgery part of the defect which extended down to the cancellous bone had been predominantly restored with newly formed lamellar bone. Only small HA remnants were still present at the bottom of the original defect. Resurfacing of the joint had occurred with fibrocartilaginous repair tissue.

The absence of adequate fixation capacity of the HA near the joint space resulted in a relative instability of the graft with progressive resorption. Therefore, HA is not a suitable biomaterial to facilitate the repair of large articular cartilage defects.